Cook pasta according to package. Drain, reserving 1/4 cup of the cooking water, and set aside.
Heat a large skillet over medium-high heat. Cook sausage (no oil needed) until browned and cooked through, breaking it up with a wooden spoon. If your sausage is really fatty you may need to use a knife to break if up into small pieces. Drain off excess grease if your sausage is greasy. Add sun-dried tomatoes and garlic and continue cooking for 2 minutes.
Stir in heavy cream, chicken broth, parmesan, and salt. Cook for 2 to 3 minutes until sauce begins to thicken.
Stir cooked pasta into the sauce and cook for 3 to 4 minutes, until sauce is sticking to pasta and is really thick and creamy. Stir in spinach for the final 1 minute just to wilt it. If your sauce gets too thick at any point, just stir in a splash of that reserved pasta water.
Serve with more parmesan if desired.